MEDRADSC 3K03 Lecture Notes - Lecture 15: Voxel, Modified Discrete Cosine Transform, White Matter

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 3K03
• Professor: Lyndsay Simmons

Document Summary

Objectives: define artifacts, so(cid:373)ethi(cid:374)g (cid:455)ou do(cid:374)"t (cid:449)a(cid:374)t i(cid:374) (cid:455)our i(cid:373)age, noise and artifacts are very similar. Identify various types of artifacts: physics based, patient based, equipment induced, recognize the appearance of the artifacts on images, suggest corrective measures, one case study on final will be centered around artifact correction, metal* or a different one. Volume averaging: reduction of snr, so when we have thinner slices, we have a reduction of snr, when imaging with isotropic voxels, we need to increase signal (ma) Motion: voluntary or involuntary, strategies: gating vs medications, motion artifacts appear as shading, streaking* or blurring of the image, essential, pt communication, comfort, acquisition time, motion artifact correction. Helical and cone beam effect: helical artifacts - occur due to the interpolation and reconstruction process. Intensity and beam geometry not identical for all rows of detectors: more pronounced for the peripheral detectors, windmill artifacts appear only in mdct helical.